KR20220034722A - Network Synchronization for Shared Spectrum Systems - Google Patents

Abstract

An electronic device, method, and BS for managing BSs in a shared spectrum. The electronic device receives synchronization measurement reports (SMRs) from the BSs and identifies, based on the SMRs, at least one synchronization source BS and at least one slave BS from the BSs. The transmission timing of the at least one slave BS is based on the transmission timing of the at least one synchronization source BS. The electronic device assigns at least one synchronization source BS to the hierarchy in the synchronization hierarchy. A synchronization source BS assigned to n=0 hierarchy provides the reference frame timing for a plurality of BSs, and a synchronization source BS assigned to n>0 hierarchy is a frame from another synchronization source BS assigned to n-1 hierarchy. get the timing The electronic device configures synchronization signals and transmits synchronization management indications (SMIs) to the plurality of BSs.

Description

Network Synchronization for Shared Spectrum Systems

BACKGROUND This disclosure relates generally to wireless communication systems, and more particularly, to synchronization of wireless base stations to facilitate base station-to-base communication in coordinated shared spectrum networks.

Efforts have been made to develop improved 5G (5G) or pre-5G communication systems to meet the demand for increased wireless data traffic after deployment of 4th generation (4G) communication systems. The 5G or pre-5G communication system is also referred to as a 'beyond 4G network' or a 'post long term evolution (LTE) system'. The 5G communication system is believed to be implemented in higher frequency (mmWave) bands, eg, 60 GHz bands, to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, large-scale multiple-input multiple-output (MIMO), FD-MIMO (full dimensional MIMO), array antenna, analog beamforming, and large-scale antenna techniques are used in a 5G communication system. are discussed about In addition, in 5G communication systems, next-generation small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving networks, Developments are underway to improve system networks based on coordinated communication, coordinated multi-points (CoMP), and receiver-end interference cancellation. In the 5G system, hybrid frequency shift keying (FSK) and Feher's quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) are used as advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal (NOMA) multiple access), and sparse code multiple access (SCMA) have been developed as advanced access technologies.

The Internet, a human-centric connected network in which humans generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities such as things exchange and process information without human intervention. The Internet of everything (IoE), a combination of IoT technology and big data processing technology through connection with a cloud server, has emerged. As technological elements such as technonologyed connected networks where humans generate and consume information now evolve into the Internet of Things (IoT), where ud servers have emeIoT implementations, sensor networks, machine-to-machine (M2M) communication , MTC (machine type communication), etc. have been recently studied. Such an IoT environment can provide intelligent Internet technology services that create new values in human life by collecting and analyzing data generated between connected objects. IoT is a smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance through the convergence and combination between existing information technology (IT) and various industrial applications. and next-generation medical services.

In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor network, MTC, and M2M communication may be implemented by beamforming, MIMO, and array antennas. The application of cloud RAN as a big data processing technology described above can also be considered as an example of convergence between 5G technology and IoT technology.

As described above, various services may be provided according to the development of a wireless communication system, and therefore, a method for easily providing these services is required.

Embodiments of the present disclosure include an electronic device and a corresponding method for managing a shared spectrum, and a base station (BS) for operating in the shared spectrum. One embodiment includes a memory comprising instructions for managing a shared spectrum, and a processor operatively coupled to the memory and configured to execute instructions, the instructions causing an electronic device to synchronize from a plurality of BSs. for an electronic device to receive synchronization measurement reports (SMRs) and to identify, based on the SMRs, at least one synchronization source BS and at least one slave BS from a plurality of BSs. The transmission timing of the at least one slave BS is based on the transmission timing of the at least one synchronization source BS. The electronic device assigns at least one synchronization source BS to the hierarchy in the synchronization hierarchy. A synchronization source BS assigned to n=0 hierarchy provides the reference frame timing for a plurality of BSs, and a synchronization source BS assigned to n>0 hierarchy is a frame from another synchronization source BS assigned to n-1 hierarchy. get the timing The electronic device configures synchronization signals and transmits synchronization management indications (SMIs) to the plurality of BSs. SMIs include (i) configured synchronization signals, (ii) an assigned hierarchy, and (iii) synchronization source/slave assignments.

Another embodiment relates to a method for managing a shared spectrum between a plurality of BSs. The method includes receiving synchronization measurement reports (SMRs) from a plurality of BSs, and identifying, based on the SMRs, at least one synchronization source BS and at least one slave BS from the plurality of BSs. include The transmission timing of the at least one slave BS is based on the transmission timing of the at least one synchronization source BS. The method also includes assigning at least one synchronization source BS to a hierarchy in the synchronization hierarchy. A synchronization source BS assigned to n=0 hierarchy provides the reference frame timing for a plurality of BSs, and a synchronization source BS assigned to n>0 hierarchy is a frame from another synchronization source BS assigned to n-1 hierarchy. get the timing

The method also includes configuring synchronization signals and transmitting synchronization management indications (SMIs) to the plurality of BSs. SMIs include (i) configured synchronization signals, (ii) an assigned hierarchy, and (iii) synchronization source/slave assignments.

Another embodiment relates to a base station operating in a shared spectrum. The BS includes a processor configured to generate a synchronization measurement report (SMR) and a transceiver operatively coupled to the processor, the transceiver configured to transmit the SMR and receive synchronization management indications (SMI). The SMI includes at least one of (i) configured synchronization signals, (ii) an assigned hierarchy (n), or (iii) synchronization source/slave assignments. In response to the transceiver receiving the assigned hierarchical group n, an over-the-air (OTA) to at least one of the at least one slave BS or another synchronization source BS assigned to the n+1 hierarchical group in the synchronization hierarchy Transmit a set of synchronization signals (OSS). If BS is assigned to n=0 hierarchy, BS transmits OSS set without reference to frame timing from other synchronization source BS, if BS is assigned to n>0 hierarchy, BS is assigned to n-1 hierarchy and transmits the OSS set based on frame timing derived from another synchronization source BS.

Other technical features may become readily apparent to a person skilled in the art from the following drawings, descriptions and claims.

Embodiments of the present disclosure provide an electronic device for managing a shared spectrum between a plurality of base stations (BSs), the electronic device comprising: a memory including instructions for managing the shared spectrum; and operatively connected to the memory a processor, the processor causing the electronic device to execute the instructions to receive synchronization measurement reports (SMRs) from a plurality of BSs, based on the SMRs, at least one from a plurality of BSs; identifying a synchronization source BS and at least one slave BS of the at least one synchronization source BS and the at least one slave BS, wherein the transmission timing of the at least one slave BS is based on the transmission timing of the at least one synchronization source BS identifying a BS, assigning at least one synchronization source BS to a hierarchy in a synchronization hierarchy, wherein a synchronization source BS assigned to an n=0 hierarchy provides reference frame timing for a plurality of BSs, n allocating the at least one synchronization source BS, configuring synchronization signals, wherein a synchronization source BS assigned to >0 hierarchy derives frame timing from another synchronization source BS assigned to n-1 hierarchy; and Sending synchronization management indications (SMIs) to a plurality of BSs, the SMIs comprising (i) configured synchronization signals, (ii) an assigned hierarchy, and (iii) synchronization source/slave assignments. Let it do what it sends SMIs.

In one embodiment, each synchronization source BS of the at least one synchronization source BS is wherein L is the supported level of synchronization source BSs in the synchronization hierarchy, n is an integer, and k is the frame offset based on the assigned hierarchy. Transmit each OSS in frame number (L*n + k).

In one embodiment, the first OSS and the second OSS include respective timing offsets based on their respective hierarchical groups, and the frame timing for the recipient of the first OSS or the second OSS is derived based on the respective timing offsets. do.

In an embodiment, the processor is further configured to execute instructions to cause the electronic device to determine that the support level of the synchronization source BSs is to be changed, and to change the number of time gaps based on the determined changes.

Accordingly, embodiments of the present disclosure provide a method for managing a shared spectrum between a plurality of base stations (BSs), the method comprising: receiving synchronization measurement reports (SMRs) from a plurality of BSs; identifying, based on the SMRs, at least one synchronization source BS and at least one slave BS from the plurality of BSs, wherein the transmission timing of the at least one slave BS is based on the transmission timing of the at least one synchronization source BS , identifying the at least one synchronization source BS and at least one slave BS, assigning at least one synchronization source BS to a hierarchy in a synchronization hierarchy, wherein the synchronization source BS assigned to the n=0 hierarchy is the at least one synchronization source providing reference frame timing for a plurality of BSs, wherein a synchronization source BS assigned to n>0 hierarchy derives frame timing from another synchronization source BS assigned to n-1 hierarchy; allocating a BS, configuring synchronization signals, and transmitting synchronization management indications (SMIs) to a plurality of BSs, the SMIs comprising (i) configured synchronization signals, (ii) an assigned hierarchy , and (iii) transmitting the SMIs, including synchronization source/slave assignments.

In one embodiment, each synchronization source BS of the at least one synchronization source BS is wherein L is the supported level of synchronization source BSs in the synchronization hierarchy, n is an integer, and k is the frame offset based on the assigned hierarchy. Transmit each OSS in frame number (L*n + k).

In one embodiment, the first OSS and the second OSS include respective timing offsets based on their respective hierarchical groups, and the frame timing for the recipient of the first OSS or the second OSS is derived based on the respective timing offsets. do.

In one embodiment, the method further comprises determining that the support level of the synchronization source BSs changes and, based on the determined changes, changing the number of time gaps.

For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, of which:
1 illustrates an exemplary networked computing system in accordance with various embodiments of the present disclosure;
2 illustrates an exemplary base station (BS) in an exemplary networked computing system in accordance with various embodiments of the present disclosure;
3 illustrates an example electronic device for managing a shared spectrum in a networked computing system in accordance with various embodiments of the present disclosure;
4 illustrates a network for spectrum sharing in accordance with various embodiments of the present disclosure;
5 illustrates another network for spectrum sharing in accordance with various embodiments of the present disclosure;
6A illustrates control signal exchange between BSs in a shared spectrum network according to various embodiments of the present disclosure;
6B illustrates resource reservation between BSs in a shared spectrum network according to various embodiments of the present disclosure;
7 illustrates a coordinated spectrum sharing framework in accordance with various embodiments of the present disclosure;
8 illustrates inter-BS timing synchronization according to various embodiments of the present disclosure;
9 illustrates transmission of an OSS in a coordinated spectrum sharing framework in accordance with various embodiments of the present disclosure;
10 illustrates alternative transmission of OSS in a coordinated spectrum sharing framework in accordance with various embodiments of the present disclosure;
11A illustrates a flowchart for transmitting OSS signals in accordance with various embodiments of the present disclosure;
11B illustrates a flow diagram for receiving OSS signals in accordance with various embodiments of the present disclosure;
12 illustrates a signal flow diagram for transmitting and receiving OSS between BSs to derive frame timing in accordance with various embodiments of the present disclosure;
13 illustrates a flowchart for transmitting OSSs by a synchronization source in accordance with various embodiments of the present disclosure;
14 illustrates another flow diagram for transmitting OSSs by a synchronization source in accordance with various embodiments of the present disclosure;
15 illustrates a flowchart for receiving OSSs by a slave BS according to various embodiments of the present disclosure;
16A illustrates an interference graph of BS nodes in a shared spectrum network according to various embodiments of the present disclosure;
FIG. 16B illustrates tree diagrams depicting the hierarchy of BS nodes in each one of the connection sets in the interference graph of FIG. 16A ;
17 illustrates communication of messages between components of a shared spectrum network in accordance with various embodiments of the present disclosure;
18 illustrates a signal flow diagram for synchronization source discovery and association in a centralized shared spectrum in accordance with various embodiments of the present disclosure;
19 illustrates a flowchart for synchronization of a BS in a centralized shared spectrum network according to various embodiments of the present disclosure;
20 illustrates a flowchart for operation of a BS scheduled for planned non-operation (PNO) according to various embodiments of the present disclosure;
21A illustrates a signal flow diagram for managing unavailability of a synchronization source in accordance with various embodiments of the present disclosure;
21B illustrates another signal flow diagram for managing unavailability of a synchronization source in accordance with various embodiments of the present disclosure;
22 illustrates a flowchart for multi-tiered group assignment of synchronization sources and slave BSs according to various embodiments of the present disclosure;
23A illustrates an interference graph depicting reallocation of BS nodes after a BS joins an established shared spectrum network according to various embodiments of the present disclosure;
23B and 23C illustrate transmission frames for OSS assignment before and after a BS joins an established shared spectrum network according to various embodiments of the present disclosure;
24A illustrates an interference graph depicting reallocation of BS nodes before and after a BS of an established shared spectrum network becomes unavailable in accordance with various embodiments of the present disclosure;
24B and 24C illustrate transmission frames for OSS assignment after a BS becomes unavailable in a shared spectrum network according to various embodiments of the present disclosure;
25 illustrates a flowchart for reallocating BSs in a shared spectrum network in accordance with various embodiments of the present disclosure;
26A illustrates a flowchart for transmitting SMRs in accordance with various embodiments of the present disclosure;
26B illustrates a flow diagram for transmitting SMIs in accordance with various embodiments of the present disclosure;
27A illustrates a signal flow diagram for transmitting SMRs in accordance with various embodiments of the present disclosure;
27B illustrates a signal flow diagram for transmitting SMIs in accordance with various embodiments of the present disclosure;
28 illustrates a signal flow diagram for adding a BS in a decentralized shared spectrum network according to various embodiments of the present disclosure;
29 illustrates a signal flow diagram for removing a BS in a decentralized shared spectrum network according to various embodiments of the present disclosure;
30 illustrates timing alignment between a synchronization source BS and a slave BS according to various embodiments of the present disclosure;
31 illustrates a signal flow diagram for timing alignment between a synchronization source BS and a slave BS according to various embodiments of the present disclosure;
32 illustrates a flowchart for timing alignment at a slave BS according to various embodiments of the present disclosure;
33 illustrates a flow diagram for timing alignment at a synchronization source in accordance with various embodiments of the present disclosure;
34 illustrates a signal flow diagram for a UE timing adjustment update procedure according to various embodiments of the present disclosure;
35 illustrates an architecture for a dedicated synchronization source in accordance with various embodiments of the present disclosure;
36 illustrates a flow diagram of a process for synchronization of shared spectrum networks in accordance with various embodiments of the present disclosure; And
37 illustrates a flow diagram of a process for managing shared spectrum networks with an unassigned BS in accordance with various embodiments of the present disclosure.
38 illustrates an electronic device in accordance with embodiments of the present disclosure; And
39 illustrates a base station according to embodiments of the present disclosure.

Before embarking on the detailed description below, it may be advantageous to refer to definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refers to any direct or indirect communication between two or more elements, whether or not they are in physical contact with each other. The terms “send,” “receive,” and “communicate,” as well as their derivatives, include both direct and indirect communication. The terms "comprises" and "comprises", as well as their derivatives, mean inclusive without limitation. The term “or” is inclusive and means “and/or”. The phrase "associated with" as well as its derivatives include, is included in, interconnects with, contains, is contained in, is contained in, connects to or to, to or to couple with, be able to communicate with, cooperate with, interleave with, juxtapose with, come close to, associate with or with, have, have the characteristics of, to or to have a relationship with, etc. The term "controller" means any device, system, or portion thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and/or firmware. Functions associated with any particular control may be centralized or distributed, whether locally or remotely. The phrase “at least one of” when used with a list of items means that different combinations of one or more of the listed items may be used and only any one item in the list may be required. For example, “at least one of A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C. Similarly, the term “set” means one or more. Thus, a set of items may be a single item or a collection of two or more items.

Moreover, the various functions described below may be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes suitable for implementation in suitable computer readable program code. , instances, related data, or portions thereof. The phrase "computer readable program code" includes computer code of any type, including source code, object code, and executable code. The phrase "computer-readable medium" means, such as read only memory (ROM), random access memory (RAM), hard disk drive, compact disc (CD), digital video disc (DVD), or any other type of memory. , including any tangible media that can be accessed by a computer. “Non-transitory” computer-readable media excludes wired, wireless, optical, or other communication links that transmit transitory electrical or other signals. Non-transitory computer-readable media includes media in which data can be permanently stored and media in which data can be stored and later overwritten, such as a rewritable optical disk or a removable memory device.

Definitions for other specific words and phrases are provided throughout this patent document. Those skilled in the art should understand that in many, if not most, if not all cases, these definitions apply to previous and future uses of the words and phrases so defined.

The drawings included in the present disclosure, and the various embodiments used to explain the principles of the present disclosure, are illustrative only and should not be construed as limiting the scope of the present disclosure in any way. Moreover, those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged wireless communication system.

a downlink (DL) through which a communication system carries signals from transmitting points, such as base stations (BSs) to receiving points, such as user equipments (UEs). include The communication system also includes an uplink (UL) that carries signals from transmission points, such as UEs, to reception points, such as BSs.

Increasing the deployment density of BSs is a way to increase data throughput through spatial reuse of frequencies. Indeed, this spatial reuse has been one of the main reasons for the increase in system throughput since the early days of cellular communication. While improving spatial reuse, dense BS deployment can be unavoidable at millimeter wave (mm wave) and terahertz (THz) frequencies to improve coverage by compensating for pathloss and blockage. there is.

Another way to increase data throughput involves the opening of unlicensed or shared spectrum. For example, in the United States, the 3.55-3.7 GHz Citizens Broadband Radio Service (CBRS) band is used for incumbent access (federal user, fixed satellite service), priority access licensees (PALs), and general authorized access (GAA). ) has a unique three-tier hierarchical access model with descending priorities. In another example, the 5925-7125 MHz band was recently approved by the FCC for unlicensed use in the United States. The 5925-6425 MHz band is under consideration by the E.U., and its regulation is expected to be completed in the near future. In another example, the 37-38.6 GHz band is expected to be open. When the FCC issued its rules for Spectrum Frontiers (5G), it was suggested that the band could be shared between commercial systems and “future” federal systems. The shared framework is expected to be distinct from the general unlicensed spectrum. Another example is the extension from the 60 GHz band to 57-71 GHz for unlicensed use. It can be seen as a global trend to open more unlicensed or shared spectrum.

Spectrum uses fluctuate temporally and geographically. Sharing spectrum through multiplexing between different entities enables more efficient use of spectrum, whether the spectrum is unlicensed or shared. As used in this disclosure, the term “shared spectrum” is used in an inclusive manner without distinction between shared and unlicensed spectrum, and includes currently available spectrum as well as spectrum that will become available in the future.

In existing unlicensed spectrums, eg 2.4 GHz, 5 GHz, channel access is based on random access, ie carrier sense multiple access/collision avoidance (CSMA/CA). CSMA/CA with exponential backoff is known to lower airtime utilization efficiency when the network is dense. Sharing is non-cooperative as it is based on regulations set by regulatory bodies and governed by fixed rules. Basically, there is no guarantee of spectrum access. Therefore, it may be disadvantageous for operators to deploy infrastructure systems for providing paid services to mobile subscribers using these unlicensed spectrums, as the reliability and accessibility of the service may not be guaranteed.

Embodiments disclosed in this disclosure relate to methods and related signaling for time synchronization between wireless base stations in a shared spectrum network. Two broad embodiments are proposed: synchronization between base stations and synchronization by dedicated synchronization sources. As used in this disclosure, “synchronization sources”, “master BS”, “master node”, “source base station”, and “synchronization source BS” may be used interchangeably.

With inter-base station synchronization, timing synchronization is achieved by transmission of wireless signals by a set of synchronization source base stations and reception of signals by other base stations. Various embodiments provide a hierarchy of master/slave relationships between master synchronization sources that transmit synchronization signals and slave base stations that listen for synchronization signals from one or more synchronization sources and use the signals to synchronize with a shared spectrum network. Describes a method for establishing and related signaling. Various embodiments also describe methods and associated signaling for centralized as well as distributed determination of master/slave relationships. Additional embodiments describe a method for resynchronization of a user equipment (UE) attached to a base station when the serving base station changes its coarse timing with associated signaling.

Dedicated synchronization sources provide a system of dedicated wireless nodes with the primary purpose of transmitting over-the-air (OTA) synchronization signals (OSS) to facilitate synchronization by many base stations over a large geographic area.

Novel aspects of the present disclosure recognize the problem of timing synchronization between base stations for shared spectrum systems. Time synchronization between base stations allows control signals to be received by other base stations at expected time offsets. Also, in a scenario in which base stations are assigned to different time slots in a TDMA scheme for interference coordination in shared spectrum networks, time synchronization ensures that proper transmission timing is within the appropriate slots.

1 illustrates an exemplary networked computing system in accordance with various embodiments of the present disclosure. The embodiment of the wireless network 100 shown in FIG. 1 is for illustrative purposes only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present disclosure.

As shown in FIG. 1 , a wireless network 100 includes a gNodeB (gNB) 101 , a gNB 102 , and a gNB 103 . gNB 101 communicates with gNB 102 and gNB 103 . The gNB 101 also communicates with at least one Internet Protocol (IP) network 130 , such as the Internet, a proprietary IP network, or other data network.

The gNB 102 provides wireless broadband access to the network 130 to a plurality of first user equipments (UEs) within the coverage area 120 of the gNB 102 . A plurality of first UEs may include a UE 111 that may be located in a small business (SB); UE 112, which may be located in a large enterprise (E); UE 113 that may be located in a WiFi hotspot (HS); a UE 114 that may be located in a first residence (R); a UE 115 that may be located in a second residence (R); and UE 116 , which may be a mobile device M such as a cell phone, wireless laptop, wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 to a second plurality of UEs within the coverage area 125 of the gNB 103 . The plurality of second UEs includes a UE 115 and a UE 116 . In some embodiments, one or more of gNBs 101 - 103 may communicate with each other and with UEs 111 - 116 using 5G, LTE, LTE-A, WiMAX, WiFi, or other wireless communication techniques. can

Depending on the network type, other well-known terms such as “base station” or “access point” may be used instead of “gNodeB” or “gNB”. For convenience, the terms “gNodeB” and “gNB” are used in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, other well-known terms such as “mobile station”, “subscriber station”, “remote terminal”, “wireless terminal”, or “user device” may be used instead of “user equipment” or “UE”. can be used For convenience, the terms "user equipment" and "UE" are used to refer to wirelessly accessing gNBs, whether the UE is a mobile device (such as a mobile phone or smartphone) or a stationary device (such as a desktop computer or vending machine). Used in this patent document to refer to remote radio equipment.

The dashed lines indicate the approximate extent of coverage areas 120 and 125 , which are shown as generally circular for purposes of illustration and description only. The coverage areas associated with gNBs, such as coverage areas 120 and 125 , may have other shapes, including irregular shapes, depending on the configuration of the gNBs and changes in the wireless environment associated with natural and man-made obstacles. It should be clearly understood that

As described in more detail below, BSs in a networked computing system may be managed to allow spectrum sharing based on interference relationships between the BSs. In some embodiments, a shared spectrum manager (SSM) in a networked computing system may provide a centralized resource coordination and allocation scheme by providing synchronization source/slave allocations and configured synchronization signals.

Although FIG. 1 shows one example of a wireless network 100 , various changes may be made to FIG. 1 . For example, wireless network 100 may include any number of gNBs and any number of UEs in any suitable arrangement. Also, the gNB 101 may communicate directly with any number of UEs and provide them with wireless broadband access to the network 130 . Likewise, each gNB 102 - 103 may communicate directly with the network 130 and provide UEs with direct wireless broadband access to the network 130 . In addition, gNBs 101 , 102 , and/or 103 may provide access to other or additional external networks, such as external telephone networks or other types of data networks.

2 illustrates an exemplary base station (BS) in accordance with various embodiments of the present disclosure. The embodiment of gNB 102 shown in FIG. 2 is for illustration only, and gNBs 101 and 103 in FIG. 1 may have the same or similar configuration. However, gNBs come in a wide variety of configurations, and FIG. 2 does not limit the scope of the present disclosure to any particular implementation of the gNB.

As shown in FIG. 2 , gNB 102 includes multiple antennas 280a-280n, multiple RF transceivers 282a-282n, transmit (TX) processing circuitry 284, and receive (RX) processing. circuit 286 . The gNB 102 also includes a controller/processor 288 , a memory 290 , and a backhaul or network interface 292 .

The RF transceivers 282a - 282n receive, from the antennas 280a - 280n, incoming RF signals, such as signals transmitted by UEs in the network 100 . The RF transceivers 282a to 282n down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are sent to RX processing circuitry 286, which generates processed baseband signals by filtering, decoding, and/or digitizing the baseband or IF signals. The RX processing circuitry 286 sends the processed baseband signals to the controller/processor 288 for further processing.

The TX processing circuitry 284 receives analog or digital data (such as voice data, web data, email, or interactive video game data) from the control/processor 288 . TX processing circuitry 284 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals. The RF transceivers 282a - 282n receive the processed baseband or IF signals transmitted from the TX processing circuitry 284 and convert the baseband or IF signals into RF signals transmitted via the antennas 280a - 280n. up-convert

The controller/processor 288 may include one or more processors or other processing devices that control the overall operation of the gNB 102 . For example, controller/processor 288 may receive and reverse forward channel signals by RF transceivers 282a-282n, RX processing circuitry 286, and TX processing circuitry 284 in accordance with well-known principles. It is possible to control the transmission of channel signals. The controller/processor 288 may also support additional functions, such as more advanced wireless communication functions. For example, control/processor 288 may support beamforming or directional routing operations in which outgoing signals from multiple antennas 280a-280n are weighted differently to effectively steer them in a desired direction. . Any of a wide variety of other functions may be supported by the controller/processor 288 in the gNB 102 . In some embodiments, control/processor 288 includes at least one microprocessor or microcontroller.

Controller/processor 288 may also execute programs and other processes resident in memory 290, such as a basic OS. Control/processor 288 may move data into or out of memory 290 as required by an executing process.

Control/processor 288 is also coupled to backhaul or network interface 292 . The backhaul or network interface 292 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. Interface 292 may support communications over any suitable wired or wireless connection(s). For example, when gNB 102 is implemented as part of a cellular communication system (such as one that supports 5G, LTE, or LTE-A), interface 292 allows gNB 102 to establish a wired or wireless backhaul connection. It may allow communication with other gNBs through When the gNB 102 is implemented as an access point, the interface 292 allows the gNB 102 to connect via a wired or wireless local area network or via a wired or wireless connection to a larger network (such as the Internet). may be allowed to communicate. Interface 292 includes any suitable structure that supports communications over a wired or wireless connection, such as an Ethernet or RF transceiver.

Memory 290 is coupled to control/processor 288 . A portion of memory 290 may include RAM, and another portion of memory 290 may include flash memory or other ROM.

As described in more detail below, base stations in a networked computing system may be assigned as either a synchronization source BS or a slave BS based on interference relationships with other neighboring BSs. In some embodiments, the allocation may be provided by the shared spectrum manager. In other embodiments, the assignment may be agreed upon by the BSs in the networked computing system. The synchronization source BSs transmit the OSS to the slave BSs to establish the transmission timing of the slave BSs.

Although FIG. 2 shows one example of a gNB 102 , various changes may be made to FIG. 2 . For example, gNB 102 may include any number of each component shown in FIG. 2 . As a specific example, an access point may include multiple interfaces 292 , and the controller/processor 288 may support routing functions to route data between different network addresses. As another specific example, while shown as including a single instance of TX processing circuitry 284 and a single instance of RX processing circuitry 286 , gNB 102 can create multiple instances of each (such as one per RF transceiver) ) may be included. Also, various components in FIG. 2 may be combined, further subdivided, or omitted and additional components may be added according to specific needs.

3 illustrates an example electronic device 300 for managing a shared spectrum in a networked computing system in accordance with various embodiments of the present disclosure. In one embodiment, the electronic device is a shared spectrum manager implemented as server 300 , which may represent server 104 of FIG. 1 .

As shown in FIG. 3 , the electronic device 300 includes a bus system 305 , which includes at least one processing device 310 , at least one storage device 315 , and at least one communication unit 320 . , and at least one input/output (I/O) unit 325 .

Processing device 310 executes instructions that may be loaded into memory 330 . The processing device 310 may include any suitable number(s) and type(s) of processors or other devices in any suitable arrangement. Exemplary types of processing devices 310 include microprocessors, microcontrollers, digital signal processors, field programmable gate arrays, application specific integrated circuits, and sophisticated circuitry.

Memory 330 and persistent storage 335 are examples of storage devices 315 , which may store information (such as temporarily or permanently, data, program code, and/or other suitable information) and Represents any structure(s) that facilitate ejection. Memory 330 may represent random access memory or any other suitable volatile or non-volatile storage device(s). Persistent storage 335 may include one or more components or devices that support longer term data storage, such as ready-only memory, hard drive, flash memory, or optical disk.

Communication unit 320 supports communications with other systems or devices. For example, the communication unit 320 may include a network interface card or wireless transceiver that facilitates communications over the network 130 . Communication unit 320 may support communications over any suitable physical or wireless communication link(s).

I/O unit 325 allows input and output of data. For example, I/O unit 325 may provide a connection for user input via a keyboard, mouse, keypad, touchscreen, or other suitable input device. I/O unit 325 may also send output to a display, printer, or other suitable output device.

As described in more detail below, electronic device 300 may act as a shared spectrum manager in a networked computing system, capable of creating synchronization source/slave assignments and configuring synchronization signals.

Although FIG. 3 shows an example of an electronic device 300 in a computing system for managing shared spectrum among a plurality of base stations, such as base stations 101 , 102 , and 103 of FIG. 1 , various changes are made to FIG. 3 . can be done about For example, the various components of FIG. 3 may be combined, further subdivided, or omitted and additional components may be added according to specific needs. Additionally, as in computing and communication networks, servers may be provided in a wide variety of configurations, and FIG. 3 does not limit the disclosure to any particular electronic device.

4 illustrates a network for spectrum sharing according to various embodiments of the present disclosure. Network 400 is a network computing system, such as networked computing system 100 of FIG. 1 .

Network 400 includes multiple BSs from different mobile network operators (MNOs), ie wireless service providers coexisting in close proximity to each other. As an example, BS 401 and BS 404 belong to the same MNO, eg, “MNO B”, and BS 402 and BS 403 belong to different operators, eg, “MNO A”. However, the specific depiction of the network of FIG. 4 is illustrative and not restrictive. Thus, in other embodiments, the number of mobile network operators may be different for different systems and technologies sharing the spectrum.

In FIG. 4 , BSs that interfere with each other are connected by dashed lines 405 . For example, BS 401 and BS 404 interfere with each other and are connected by a broken line 405a; BS 401 and BS 402 interfere with each other and are connected by a broken line 405e; BS 402 and BS 404 interfere with each other and are connected by a broken line 405d; BS 403 and BS 404 interfere with each other and are connected by a broken line 405b; BS 403 and BS 402 interfere with each other and are connected by a broken line 405c. BS 401 and BS 403 are separated by a sufficient distance to prevent interference with each other.

Each of the BSs 401 , 402 , 403 , and 404 are connected to a Shared Spectrum Manager (SSM) 406 by their respective backhaul links 407 . The SSM 406 is one or more electronic devices for managing the shared spectrum, such as the electronic device 300 of FIG. 3 . In a non-limiting embodiment, SSM 406 is an entity in each MNO's core network and is configured to communicate with each other to manage shared spectrum between BSs of all MNOs. In another non-limiting embodiment, the SSM 406 is a third-party entity that does not belong to any of the MNOs but is configured to communicate with networks of different operators to manage the shared spectrum between the BSs of the MNOs.

5 illustrates another network for spectrum sharing according to various embodiments of the present disclosure. Network 500 is a network computing system, such as networked computing system 100 of FIG. 1 .

Network 500 differs from network 400 in that each BS communicates with its MNO core network (CN) via backhaul links 507 rather than directly with SSM 406 . 5, BSs 402 and 403 communicate with CN entity 504a via backhaul links 507a and BSs 401 and 404 communicate with CN entity 504b via backhaul links ( 507b). CN entities 504a and 504b communicate with SSM 406 via their respective communication links 510 . CN entities 504a and 504b may handle the aggregation of data and/or delivery of messages such as measurement reports from BSs to SSM 406 . CN entities may also handle the establishment of BSs based on parameters in these messages along with handling the receipt of messages from SSM 406 on behalf of the BSs.

6A illustrates control signal exchange between BSs in a shared spectrum network according to various embodiments of the present disclosure. Network 600a is part of a shared spectrum network, such as network 400 of FIG. 4 , that includes a depiction of an exchange of over-the-air (OTA) control signals for coordinating and reserving spectrum resources. In this exemplary embodiment of FIG. 6A , MNO B BS1 sends coordination request signals 602a , 602b , and 602c to MNO A BS1 , MNO A BS2 , and MNO B BS2 respectively. MNO B BS1 responds by receiving coordination response signals 604a and 604c from the interfering BSs MNO A BS1 and MNO B BS2.

6B illustrates resource reservation between BSs in a shared spectrum network according to various embodiments of the present disclosure. Resources are reserved by the BSs in FIG. 6A. In particular, spectrum sharing is achieved by BSs belonging to different MNOs from network 600a. Since the BSs MNO A BS2 and MNO B BS1 are geographically separated from each other and are not in an interfering relationship, as indicated by the lack of a broken line connecting the two, both of the BSs can transmit simultaneously. On the other hand, MNO A BS1, MNO B BS1, and MNO B BS2 are connected by broken lines and are in an interference relationship. Therefore, they share resources in an orthogonal manner. Sharing may be enabled in time and/or geographic domains. In other words, spectrum may be shared in a time division multiplexing (TDM) manner between systems/technology, and/or spectrum may be simultaneously shared by geographically separated systems/technology through spatial reuse. can be reused. The sharing framework disclosed in embodiments of the disclosed system may achieve the above time and/or geographic sharing in a localized and autonomous manner.

7 illustrates a Coordinated Spectrum Sharing Framework (CSS) in accordance with various embodiments of the present disclosure. The CSS framework depicts resources shared between BSs in a shared spectrum network, such as network 400 of FIG. 4 .

An embodiment of a coordinated spectrum sharing (CSS) framework may include a coordination phase (CP) and a data transmission phase (DTP), which enable spectrum sharing. Each CSS frame includes an adjustment phase (CP) 702 and a data transmission phase (DTP) 704 . CP 702 may be used for OTA communications between BSs of the same/different operators.

Each CSS frame has a CSS frame period 706 having a predetermined duration. CSS frame period 706 includes CP period 710 corresponding to CP 702 and DTP period 708 corresponding to DTP 704 . During the CP period 710 , each BS may perform identification of neighboring BSs, parameter negotiation, resource reservation for the next DTP and/or other DTPs, and other coordination operations. Coordinated data transmissions by the BSs may be sent and received during the DTP period 708 based on resource reservations made during the CP period 710 . Opportunistic data transmission may also occur based on a listen-before-talk (LBT) protocol during the DPT period 708 when the reserved medium is not being used. In another embodiment, CP 702 and DTP 704 may use different frequency or code resources.

8 illustrates inter-BS timing synchronization according to various embodiments of the present disclosure. Time synchronization is performed between the BSs of a shared spectrum network by transmission of wireless signals from a set of synchronization source base stations to a set of recipient base stations.

In the exemplary embodiment of FIG. 8 , one or more OSSs 800 may be transmitted by one or more BSs in a shared spectrum network to enable other BSs to be synchronized. As previously discussed, the transmission of OSS 800 may be triggered periodically with any duty cycle or pattern, or aperiodically by some event, such as a signal from another BS or network entity. Although the OSS 800 is depicted as being transmitted in the DTP of FIG. 8 , in other embodiments, the OSS 800 may instead be transmitted in the CP. It is also possible that the OSS transmission occurs during the dedicated synchronization signal transmission period and not as part of the CP or DTP.

9 illustrates transmission of an OSS in a coordinated spectrum sharing framework in accordance with various embodiments of the present disclosure. In the framework 900 , an OTA synchronization signal (OSS) is transmitted at the beginning of a shared spectrum system frame, eg, at the beginning of a CP. In other embodiments, the OSS may be transmitted to the CP or elsewhere to the DTP.

The 0th tier synchronization source 902 transmits OSSs 908a and 908b based on its frame timing. OSSs 908a and 908b are transmitted in frame numbers (L*n + k), where L is the supported hierarchy of synchronization sources, k is the frame offset, and n is an integer. In the above exemplary diagram, L=3, k=0 for the 0th hierarchical group synchronization source.

The first hierarchical sync source 904 obtains frame timing based on the OSS 908 received from the lower level (which is at the level number) sync source. In this example of FIG. 9 , sync source 904 obtains its frame timing based on OSS from sync source 902 .

The frame offset number for the sync source 904 is based on its hierarchy to determine which frames to transmit OSSs on. For example, sync source 904 transmits OSSs 910a and 910b at L=3, k=1, and frame numbers where n is an integer (L*n+k). OSSs 910 include a system frame number (SFN). Sync source 906 transmits OSS 912a at L=3, k=2, and frame number (L*n+k) where n is an integer. OSSs 912 also include a corresponding SFN.

10 illustrates an alternative transmission of an OSS in a coordinated spectrum sharing framework in accordance with various embodiments of the present disclosure. In the framework 1000, the OSS transmission period is predefined and OSSs from different sync source hierarchies are staggered. In this example of FIG. 10 , the OSS transmission period is before the CP and is configured to support up to three synchronization sources, ie, up to the second hierarchical group synchronization source.

The OSS transmission period occurs every N frames. In the depicted example, N=1 so that the OSS transmission occurs every frame. The 0th hierarchical group synchronization source 1002 transmits the OSSs 1008a and 1008b based on its frame timing. Depending on the depth of the OSS transmission period, it indicates a time interval based on the start of the frame, eg t1 in the example above. OSS includes SFN.

The first hierarchical group and the second hierarchical group synchronization sources obtain frame timing based on the OSS received from the lower hierarchical group synchronization source. For example, synchronization source 1004 obtains its frame timing for OSS transmission periods 1010a and 1010b from OSS transmission periods 1008a and 1008b, and synchronization source 1006 obtains its frame timing for OSS transmission periods 1010a and 1010b. It obtains its frame timing for OSS transmission periods 1012a and 1012b from 1010a and 1010b).

In some embodiments, OSS transmission timing offsets are determined within an OSS transmission period based on a synchronization source hierarchy and the OSSs are transmitted based on a corresponding time interval at the determined timing offset. For example, t1 for sync source 1004 and t2 for sync source 1006 . The SFN received from the 0th layer group synchronization source 1002 is repeated in the transmitted OSSs, eg, OSS 1010a, 1010b, 1012a and 1012b.

11A illustrates a flow diagram for transmitting OSSs in accordance with various embodiments of the present disclosure. The operations of flowchart 1100a may be implemented in a BS, such as BS 200 of FIG. 2 .

Flowchart 1100a begins at operation 1102 by detecting a trigger. A trigger may be periodic, such as a timer, or may be aperiodic, such as an event or signal from another BS or network entity in the spectrum sharing network, such as SSM 406 of FIG. 4 . At operation 1104 , the OSS is transmitted to another BS.

11B illustrates a flow diagram for receiving OSSs in accordance with various embodiments of the present disclosure. The operations of flowchart 1100b may be implemented with a BS, such as BS 200 of FIG. 2 .

In operation 1106 an OSS is received. Based on the received OSS, frame timing is updated in operation 1108 . In some embodiments, flowchart 1100b may also include the operations of flowchart 1100a in which the BS receiving OSS signals is a master BS for one or more slave BSs, as shown in more detail in FIG. 12 . there is.

Each of the BSs that transmit and receive OSS signals may belong to different MNO networks. In one embodiment, the BSs may initially receive the OSS to establish their frame timing once. In another embodiment, the BSs may continuously update their frame timing based on the received OSS, periodically triggered by some timer, or after being triggered by some event or signal from another BS or network entity. You can do that aperiodically.

12 illustrates a signal flow diagram for transmitting and receiving OSS between BSs to derive frame timing in accordance with various embodiments of the present disclosure. In this example, BS A 1202 is the synchronization source for BS B 1204 . BS B 1204 is a slave BS to BS A 1202 and is also a synchronization source to BS C 1206 . BS C 1206 is a slave BS to BS B 1204 .

BS A 1202 sends OSS to BS B in S1208. BS B 1204 uses the OSS received from BS A 1202 to derive its frame timing in S1210. BS B 1204 sends OSS to BS C 1206 in S1212. At S1214 BS C 1206 derives its frame timing from the OSS received from BS B 1204 .

The BSs depicted in FIG. 12 are BS A 1202 which is a root node in the 0th level hierarchy, BS B 1204 which is a node in the 1st level hierarchy, and a node in the 3rd level hierarchy. It can be depicted in a tree structure based on BS C 1206 . An example of a hierarchical tree structure for allocating BS nodes to hierarchies is depicted and discussed in greater detail in FIG. 16B .

13 illustrates a flow diagram for transmitting OSSs by a synchronization source in accordance with various embodiments of the present disclosure. The operations of flowchart 1300 may be implemented in a BS, such as BS 200 of FIG. 2 . More specifically, the operations of flowchart 1300 may be implemented by a synchronization source BS in the 0th level hierarchy, such as BS A 1202 of FIG. 12 .

Flowchart 1300 begins at operation 1302 by detecting a trigger. A trigger may be periodic or aperiodic. One example of an aperiodic trigger is an OSS transmission request from another BS in a shared spectrum network. At operation 1304 , an OSS transmission instance is determined. At operation 1306 , a system frame number (SFN) and frame start offset are encoded into the OSS message. The OSS message is sent to operation 1308 .

14 illustrates another flow diagram for transmitting OSSs by a synchronization source in accordance with various embodiments of the present disclosure. The operations of flowchart 1400 may be implemented in a BS, such as BS 200 of FIG. 2 . More specifically, the operations of flowchart 1400 may be implemented by a synchronization source that is not in the 0th level hierarchy, such as BS B 1204 of FIG. 12 .

Flowchart 1400 begins at operation 1402 by detecting a trigger. A trigger may be periodic or aperiodic. At operation 1404 , an OSS is received from a synchronization source in a lower hierarchy. At operation 1406 , timing synchronization is performed using the received OSS and an SFN is derived.

At operation 1408 , an OSS transmission is determined. At operation 1410 , the SFN and/or frame start offset is encoded in the OSS message. An OSS message is sent in operation 1412 .

15 illustrates a flowchart for receiving OSSs by a slave BS according to various embodiments of the present disclosure. The operations of flowchart 1500 may be implemented in a BS, such as BS 200 of FIG. 2 . More specifically, the operations of flowchart 1500 may be implemented by a slave BS, such as BS C 1206 of FIG. 12 .

Flowchart 1500 begins at operation 1502 by detecting a trigger to perform synchronization. A trigger may be periodic or aperiodic. An example of a trigger is to detect asynchronization. At operation 1504 , OSS reception is performed. The OSS is received from a synchronization source in a lower hierarchy.

In operation 1506 a determination is made as to whether an OSS is received. If no OSS is received, flow chart 1500 returns to operation 1504 . However, if an OSS is received, flow diagram 1500 proceeds from operation 1506 to operation 1508 where a determination is made as to whether multiple OSSs are received. If multiple OSSs are not received, timing synchronization is performed based on the received OSS and an SFN is derived in operation 1510 . However, if multiple OSSs are received in operation 1508 , the flowchart 1500 proceeds to operation 1512 where an OSS is selected from the multiple OSSs received. Flowchart 1500 then proceeds to operation 1510 .

The relationships between BSs that transmit OSS at a given timing and other BSs that receive OSS to derive their CSS frame timing create a hierarchy of master BSs (i.e. OSS transmitters) and slave BSs. . The hierarchy is depicted in FIGS. 16A and 16B , where BSs are depicted as nodes with interference relationships depicted by dashed lines.

16A illustrates an interference graph of BS nodes in a shared spectrum network according to various embodiments of the present disclosure. In this non-limiting example, BS node A through BS node J participate in the CSS network. Dashed lines between BS nodes indicate interference relationships between two BS nodes, indicating that the interference power between a pair of nodes exceeds a certain threshold. A pair of nodes having an interference relationship means that a signal, eg, OSS, transmitted from one node can be received at another node.

As shown, the interference graph 1600 can be partitioned into two subgraphs or connection sets 1600a and 1600b, each of which does not have any interfering relationships with a BS node in the other connection set. Contains a set of BS nodes. In this case, the timing of each connection set may be established independently of the other connection sets, where OTA signals in the CP may not need to be received by the BSs of the other connection set, control message transmission opportunities or This is because there may not be significant interference between BSs of different connection sets from data slot timing misalignment.

Within each connection set, the BS synchronizes to one or more neighboring BSs following the general procedure of FIG. 12 . The resulting hierarchical structure may be visualized in the form of a tree structure illustrated in FIG. 16B .

FIG. 16B illustrates tree diagrams depicting the hierarchy of BS nodes in each one of the connection sets in the interference graph of FIG. 16A . Each of the hierarchical trees 1600c and 1600d is rooted in one master synchronization source that provides the reference timing for the entire set of connections.

The dashed lines in FIG. 12B indicate the master/slave synchronization relationship, where the slave BSs can derive their timing from the OSS signal of each master. Each connection set may have at least one route synchronization source and may have multiple routes. If multiple BS nodes with Global Positioning System (GPS) or Precision Time Protocol (PTP) based absolute timing references are available within a connection set, multiple routes that can be designated are: It makes it possible to transmit them with the same exact timing and can lead to more accurate synchronization of the connection set. A number of hops or intermediate synchronization source nodes between a given node and a root in the synchronization hierarchy are referred to as a hierarchy in this disclosure. Root nodes are said to be in hierarchy 0, nodes synchronized directly to the root are in hierarchy 1, nodes synchronized to hierarchy 1 nodes are in hierarchy 2, and so on. Each successive hierarchy after hierarchy 0 may introduce higher timing errors, i.e., deviations from the root reference timing for the connection set, due to inaccuracies in estimating the timing from the received OSS(s). . Thus, this error can be propagated and further complicated by each intermediate synchronization source below the root in the hierarchy. Procedures for selecting a synchronization source and establishing this layered hierarchy are presented in later sections of this disclosure.

OTA Synchronization Signals

As discussed, OSS are signals transmitted by BSs to facilitate synchronization of other BSs. In one embodiment, OSS is used for Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) transmitted by LTE base stations for user equipment (UE) synchronization, respectively It can take the form of a simple pulse of RF energy or a training sequence, for example a Zadoff-Chu or M-sequence. In another embodiment, if the base stations already transmit synchronization signals such as LTE PSS/SSS for UE synchronization, the same signals may be reused for inter-BS synchronization. Alternatively, the BSs may transmit a separate OSS in addition to the UE synchronization signals. Additionally, in a further embodiment, the OSS may include system information that may be decoded by the receiving BSs. Such system information may include, but is not limited to:

BS ID (eg, physical cell ID, cell global identifier, etc.);

network or Public Land Mobile Network (PLMN) ID, and/or

An indicator of the availability of an absolute (eg GPS or PTP) timing source in the BS and/or in the BS's synchronization source hierarchy.

The same information elements may be transmitted as part of OSS or standard system information signals transmitted by BS for UE initial attach, for example Master Information Block (MIB) or system information in LTE system. may be included in System Information Block (SIB) signals.

Set up a centralized sync source

In some embodiments, management of timing synchronization in CSS is accomplished by a central network entity. The central network entity may be the SSM 406 , as shown in FIG. 17 .

17 illustrates communication of messages between components of a shared spectrum network in accordance with various embodiments of the present disclosure. Network 1700 is a shared spectrum network, such as network 400 of FIG. 4 .

The central network entity, SSM 406, is responsible for assisting BSs joining the network to discover synchronization sources and synchronize with the network or set of connections. SSM 406 also handles network topology or configuration changes in other cases, such as when a synchronization source goes offline or becomes unavailable or when interference relationships between BSs change.

The SSM 406 sends synchronization management indication (SMI) messages 1704a and 1704b to the BSs over their respective backhaul links, which may be wired or wireless, or the core network, as shown in FIG. 17 . The configuration of the CSS network 1700 may be managed. Additionally, BSs may report information to SSM 406 via Synchronization Measurement Report (SMR) messages 1702a and 1702b over Backhaul/CN. Details of these messages and procedures for onboarding a new BS and handling topology changes are given in the following sections.

Centralized discovery and association of new base station synchronization sources

BSs that are newly installed, or activated after a period of inactivity, may be needed to (re)discover neighboring synchronization sources and associate them with the master BS. In the exemplary centralized synchronization source discovery and association procedure shown in FIGS. 18 and 19 , BS synchronization source discovery and association with the master BS is facilitated by the SSM entity.

18 illustrates a signal flow diagram for synchronization source discovery and association in a centralized shared spectrum in accordance with various embodiments of the present disclosure. In this non-limiting example of FIG. 18 , BS B 1802 has been newly activated in a shared spectrum network that already includes SSM 1804 and BS A 1806 , such as network 400 of FIG. 4 .

At s1808, BS B 1802 sends a request for SMI. In one embodiment, the request may be a keep-alive signal that is a simple indication of BS activity. In another embodiment, the request will be included as part of an SMR that may include system information about BS B 1802, including an indication of the availability of GPS or P2P timing reference or geographic coordinates of BS B 1802. can The SMR may also include an indication of whether BS B 1802 will allow BS B 1802 to be designated as the synchronization source, which BS B 1802 cannot serve as the synchronization source or transmit OSSs. This is because it may be a case of not serving as a motivational source for BS B 1802 may also indicate in the SMR that it requests or prefers a BS to be assigned as its synchronization source in the same MNO network or PLMN.

At s1810 SSM 1804 responds to the request with an SMI message that may include neighbor discovery support information to assist BS B 1802 discovering neighbor BSs. The neighbor discovery information may include, as an example, a synchronization sequence index or IDs of other BSs in the same geographic area, which may be used by a new BS to determine a set of synchronization sequences to be transmitted as part of an OSS to search. can Narrowing the search space of possible OSS sequences to a limited set can reduce the delay involved in blindly searching all possible OSS sequences and discovering neighboring synchronization sources.

In s1812, BS B 1802 performs a neighbor discovery procedure by scanning OSS signals of neighboring BSs. In operation s1814 , BS B 1802 sends an SMR including the found neighboring BS IDs to SSM 1804 . Additional information about neighboring BSs, such as PLMN ID, synchronization source status (ie BS is an active synchronization source) and hierarchy may also be included. This information may be detected from the neighboring BSS OSS, MIB or SIB.

At s1816 , the SSM 1804 may respond to the SMR transmitted at s1814 with an SMI including configuration information such as master synchronization source assignment for BS B 1802 . In some embodiments, SMI may designate BS B 1802 as the synchronization source. In these embodiments, the sequence index used to generate the synchronization sequence may be specified in the SMI. SSM 1804 may determine that the settings of other BSs, eg, BS A 1806, also need to be updated as a result of BS B 1802 being activated. Thus, at s1818 SSM 1804 sends other BSs to one or more other BSs in the shared spectrum network in addition to BS B 1802, possibly such as changing their master synchronization source and updating their own frame timing. , can send an SMI that can trigger to update their settings.

For example, at s1818 the SMI transmitted from SSM 1804 to BS A 1806 sends BS A 1806 as a synchronization source BS to reserve some uplink resources for inter-BS communication from BS B 1802. can be set. These uplink resources are a random access channel that will be used for BS B 1802 to perform a random access procedure towards master BS A 1806 to obtain this information as a timing advance (TA). (RACH) time/frequency resources and/or random access preamble. Additional details on inter-BS information request/response and timing advance are disclosed in later sections.

At s1820 , BS B 1802 sends an acknowledgment to SSM 1804 and at s1822 , BS A 1806 sends an acknowledgment to SSM 1804 . At s1824, BS B 1802 may apply the settings from the previous SMI received at s1816, which entails making the slave BS a designated master, such as BS A 1806, or a synchronization source. can do. When BS B 1802 is instructed to become slave BS B 1802, it can set its own frame timing according to the specified master's OSS. BS B 1802 may also continue to monitor additional OSSs sent by the master and update its frame timing. Alternatively, if BS B 1802 is designated as the synchronization source, it may also start transmitting OSS with the settings provided in SMI of s1816.

At s1826, BS A 1806 also applies the settings of the SMI received at s1818 to update its synchronization configuration, eg, RACH or other uplink resource for inter-BS communication from BS B 1802. can be reserved.

One or more operations in the procedure may be optional and in an alternate order without compromising the general purpose of discovery of neighboring synchronization sources by the new BS and/or setting of synchronization-related parameters of the new BS by a centralized SSM entity. may be performed or omitted.

In general, if the added or removed BS is not a synchronization source, its addition or removal does not affect the system frame timing. If the added BS does not find the synchronization source, the added BS becomes the 0th hierarchical group synchronization source and can serve as the basis for frame timing. If the added BS is designated as the nth hierarchical group synchronization source where n>0, it will regenerate the OSS based on the timing obtained from the n-1st hierarchical group. Since it is an existing frame timing regeneration, it does not affect the frame timing.

If the removed BS is the synchronization source and there are BSs based on timing from the removed BS, then the new BS needs to be designated as the synchronization source. The new sync source BS derives the timing from the lower level sync source, and the existing frame timing is not changed. When the new synchronization source becomes the 0th hierarchical group synchronization source, the frame timing may be reset.

19 illustrates a flowchart for synchronization of a BS in a centralized shared spectrum network according to various embodiments of the present disclosure; The operations of the flowchart 1900 may be implemented in a BS newly joining an established shared spectrum network, such as the BS 200 of FIG. 2 .

Flowchart 1900 begins by being turned on in operation 1902 . At operation 1904 , a scan is performed on the OSS for a given duration. A determination is then made in operation 1906 as to whether an OSS is received. Once the OSS is received, flowchart 1900 proceeds to operation 1908 where timing synchronization is performed and an SFN is derived. At operation 1910 , an SMR is transmitted to the SSM. The SSM may, in response to receiving the SMR report, designate a new BS implementing flowchart 1900 as a higher level synchronization source (ie, not a root level synchronization source). This new BS may then follow the operations of flowchart 1400 .

Returning to operation 1906 , if a determination is made that no OSS is received, then in operation 1912 designation as the 0th tier synchronization source is assumed and the flowchart 1900 proceeds to operation 1910 .

20 illustrates a flowchart for operation of a BS scheduled for planned non-operation (PNO) according to various embodiments of the present disclosure. The operations of the flowchart 2000 may be implemented in a BS, such as the BS 200 of FIG. 2 . In particular, the BS is scheduled for a planned non-operation (PNO).

Flowchart 2000 begins at operation 2002 by determining whether to act as a synchronization source. If a determination is made not to act as a synchronization source, the flow diagram ends. However, if it is determined to serve as a synchronization source for one or more BSs, then flowchart 2000 proceeds from operation 2002 to operation 2004 and reports the PNO to the SSM. The flowchart ends thereafter.

In response to receiving the SMR reporting the PNO to the SSM, the SSM may adjust the synchronization source/slave relationships of its BSs.

Centralized Synchronization Source Reconfiguration

Changes in the network topology, such as addition of a BS, a BS becoming inactive or otherwise unavailable, or changes to interference relationships between BSs may prompt the SSM to reassign synchronization sources to one or more BSs. can Examples are described in more detail in FIGS. 21A and 21B .

21A illustrates a signal flow diagram for managing unavailability of a synchronization source according to various embodiments of the present disclosure. In signal flow diagram 2100a , BS B 2102 , SSM 2104 , and BS A 2106 are in a shared spectrum network, such as network 400 of FIG. 4 . In addition, BS B 2102 is a synchronization source.

At s2108, BS B 2102 determines that it will become unavailable. For example, BS B 2102 may be scheduled for a planned non-operation (PNO) event. At s2110 , BS B 2102 sends an SMR to SSM 2104 with a Node Unavailability indication indicating that it will no longer act as an active synchronization source in the shared spectrum network. At s2112 , SSM 2104 sends an SMI to BS A 2106 to inform BS A 2106 of updated master/slave assignments. In one embodiment, BS A 2106 is promoted to a synchronization source. At s2114, BS A 2106 sends an acknowledgment back to SSM 2104. Upon receipt of the acknowledgment, SSM 2104 sends an SMI to BS B 2102 to release BS B 2102 as the synchronization source at s2116. At s2118, BS B 2102 is turned off and at s2120 BS A 2106 sets its synchronization parameters using the information included in the SMI transmitted at s2112.

21B illustrates another signal flow diagram for managing unavailability of a synchronization source according to various embodiments of the present disclosure. In signal flow diagram 2100b , SSM 2104 , BS A 2106 , and BS C 2108 are in a shared spectrum network, such as network 400 of FIG. 4 . Furthermore, BS C 2108 is a slave BS that has determined that its synchronization source has become unavailable.

At s2120, BS C 2108 determines that its synchronization source is unavailable. For example, BS C 2108 monitors the OSS of neighboring synchronization sources, e.g., BS B, possibly BSs being deactivated, experiencing faults or failures, in radio channels that affect OSS signal reception. Variation, or other factors, may determine whether the synchronization source is no longer available as a synchronization source.

At s2122 , BS C 2108 sends an SMR to SSM 2104 indicating that its synchronization source is no longer available. At s2124 , SSM 2104 sends an SMI to BS C 2108 to inform BS C 2108 of updated master/slave assignments. SSM 2104 also sends an SMI to BS A 2106 to inform BS A 2106 of updated master/slave assignments. At s2128 , BS C 2108 sets its synchronization parameters based on the received SMI, and at s2130 , BS A 2106 sets its synchronization parameters based on the received SMI.

Exemplary Options for Assigning a Synchronization Source

Although the criteria for assigning a synchronization source to a BS may vary from implementation to implementation, several possible approaches or policies may be considered. In one embodiment of centralized synchronization assignment, the SSM may designate the neighbor synchronization source in the lowest hierarchy, or the lowest hierarchy in the same MNO network or PLMN, as the master for the new BS. While other policies are possible, an SSM that can assign a BS to a master in the lowest available hierarchy can achieve the lowest timing error, which, as mentioned, will propagate through successive hops of intermediate OTA synchronization sources. because it can If multiple synchronization sources in the same hierarchy are neighbors of the new BS, the SSM may indicate in the SMI that the BS should average the timings derived from these synchronization sources to reduce timing errors for both neighboring nodes. there is. In another embodiment, the SSM may indicate that the BS should take a weighted average of timings derived from multiple neighboring synchronization sources that may be in different hierarchies. In this embodiment, the weights applied to the timings derived from each synchronization source, e.g., each timing from a lower hierarchy will receive a higher weight, since errors from the root timing reference may be less. may be a function of the hierarchical group of

22 illustrates a flowchart for multi-tier group assignment of synchronization sources and slave BSs according to various embodiments of the present disclosure. The operations of flowchart 2200 may be implemented with an SSM, such as SSM 406 of FIG. 4 .

Flowchart 2200 begins at operation 2202 by selecting a hierarchical group N equal to zero. In operation 2204 , one or more nodes are assigned to act as synchronization sources in the Nth hierarchy. At operation 2206 , one or more nodes are assigned to receive synchronization signals from one or more synchronization nodes in the Nth tier.

In operation 2208 a determination is made as to whether the unassigned node still exists. If there are still unassigned nodes, the flow chart 2200 proceeds to operation 2214 where the hierarchy is incremented by one, ie, N=N+1, before returning to operation 2204 . However, if a determination is made in operation 2208 that no unassigned node exists, the flow chart 2200 proceeds to operation 2210 where data is transmitted using the identified resources. At operation 2212 , an SMI is sent to the BSs indicating that the BSs may need to update their synchronization source assignments and/or settings.

Moreover, addition or removal of a BS node from the shared spectrum network topology may result in a synchronization source reassignment by the SSM to one or more BS nodes. The addition and removal of BSs is described in more detail in the interference graphs shown in FIGS. 23 and 24 .

23A illustrates an interference graph depicting reallocation of BS nodes after a BS joins an established shared spectrum network according to various embodiments of the present disclosure. The BSs of network 2300a are initially split into two separate connection sets, connection set 1 2302 and connection set 2 2304 .

The addition of a new BS node, e.g., BS Node B, having an interfering relationship with nodes from both connection set 1 2302 and connection set 2 2304 causes two independent connection sets to be joined into one connection set. something to do. For example, if BS Node B has interference relationships with BS Nodes C, G, and H from Connection Set 1 and with BS Node A from Connection Set 2, then the SSM will share the spectrum as shown in network 2300a'. A network can be reconfigured into a single set of connections.

In network 2300a, each set of connections 2302 and 2304 may have a different root synchronization source and have significantly different CSS frame timings. In this situation, the SSM may reassign the synchronization sources such that, as an example, BS Node B becomes the root synchronization source and A and G become slaves to B, thus demoted to Tier 1 nodes. BS nodes A, G or both may need to update their frame timing according to the timing of BS Node B. Although the slave nodes of A and G still remain as slaves to the same synchronization sources, they may also be required to update their approximate timing as a result. Alternatively, the SSM could assign a new BS Node B with either BS Node A or G as the master, perhaps based on the estimated interference it would cause to the other set of connections if BS Node B had not been synchronized. there is. To further explain this example, BS Node B can only weakly interfere with A and vice versa, while causing significant interference with BS Nodes C, G and H. In this case, the SSM determines that BS Node B should be assigned to its master synchronization source, BS Node G, thus avoiding re-synchronization and resynchronization of multiple nodes from both connection sets.

In one example, BS node G is the synchronization source for connection set 1 2302 and BS node A is the synchronization source for connection set 2 2304 . BS Node B is newly activated in network 2300a and starts exchanging signals with SSM (not shown). An example of a signal exchange between a BS Node B and an SSM is shown in the signal flow diagram 1800 of FIG. 18 . Although not shown in FIG. 18 , the signals that were exchanged between SSM 1804 and BS A 1806 are also affected by the addition of SSM 1804 and BS Node B to various BS nodes, e.g., BS Node C. , G, and H will be transmitted.

23B illustrates transmission frames for network 2300a before BS Node B is activated. Because BS nodes A and G are separate connection sets, they can both transmit OSS as tier 0 synchronization sources in OSS transmission periods 2306a, 2306b, 2306c, 2306d, and 2306e.

23C illustrates transmission frames for network 2300a' before BS Node B is activated. In this example, BS Node B is assigned as the synchronization source BS of network 2300a' and transmits as the 0th tier synchronization source in OSS transmission periods 2308a and 2308b. BS Nodes A and G are reassigned as first tier synchronization sources that derive their transmission timing from BS Node B. In particular, BS nodes A and G transmit OSS in OSS transmission periods 2310a and 2310b using spatial reuse.

24A illustrates an interference graph depicting reallocation of BS nodes after a BS of an established shared spectrum network becomes unavailable in accordance with various embodiments of the present disclosure. In this example, BS Node B is the root synchronization source for its set of connections in network 2400a, but may experience some hardware glitches or failures that cause BS Node B to no longer be a working synchronization source. BS B may then send a node unavailable message to SSM to indicate that it is no longer operating. The SSM may then segment the aggregated connection set into connection set 1 2402 and connection set 2 2404 in reconfigured network 2400a ′. The SSM may assign new synchronization sources to each set of connections. For example, BS node G may be assigned as the synchronization source for connection set 1 2402 and BS node A may be assigned as the synchronization source for connection set 2 2404 . The nodes of each newly formed connection set may also need to update their frame timing accordingly.

An example of a signal flow between a BS Node B and an SSM to notify the SSM of a scheduled unavailability, such as a PNO event, is discussed in greater detail in FIG. 21A . Although not shown, BS Node G will also exchange signals with SSM 2104 similar to those exchanged between SSM 2104 and BS A 2106 in FIG. 21A .

24B illustrates transmission frames 2400b for network 2400a before BS Node B becomes unavailable. As the synchronization source BS for network 2400a, BS Node B transmits OSS in OSS periods 2406a and 2406b. BS Nodes A and G are slaves to BS Node B, but are the first tier synchronization sources for one or more slave BSs. Accordingly, BS nodes A and G transmit OSS in OSS periods 2408a and 2408b using spatial reuse.

24C illustrates transmission frames 2400c for network 2400a' after BS Node B becomes unavailable. BS nodes A and G are reassigned as the 0th hierarchical synchronization sources in their respective isolated connection sets. As previously discussed, BS nodes A and G transmit OSS in OSS transmission periods 2406a and 2406b using spatial reuse.

Upon reduction of the supported synchronization source levels from two to one in this specific example of FIG. 24 , the OSS transmission duration may be reduced. The period between two consecutive OSSs from one synchronization source may be variable. There may be several period options that synchronization slave Node Bs can assume for hypothesis testing.

25 illustrates a flowchart for reallocating BSs in a shared spectrum network in accordance with various embodiments of the present disclosure. The operations of flowchart 2500 may be implemented in an SSM, such as SSM 406 of FIG. 4 .

Flowchart 2500 begins at operation 2502 where monitoring is performed for a new node or disabling of an existing synchronization source. In operation 2504, a determination is made as to whether a new node has been added, or whether an existing synchronization source has been disabled. If no new nodes have been added or the existing synchronization sources have not been disabled, the flow diagram 2500 returns to operation 2502 . However, if a new node has been added or an existing synchronization source node has been disabled, flow diagram 2500 proceeds from operation 2504 to operation 2506 and performs operations for node relocation. One non-limiting embodiment of a flowchart for node relocation is described above in FIG. 22 .

Synchronization Measurement Reports

SMR messages may be transmitted via a backhaul from the BS to the SSM, as shown in FIG. 17 . SMRs may include any one or more of the following informational elements.

Request for synchronization information. A request for synchronization information is an explicit request submitted to the SSM. This request may prompt the SSM to send the SMI along with the requested information to the transmitting BS. The requested information may include a synchronization source assignment request, or any one or more SMI information elements described in more detail in the section that follows.

Updating the system information of the transmitting BSs. The system information update for the transmitting BSs may include an indication of the ID of the BS (PCI, ECGI or some other identifier), the MNO network or PLMN ID, and/or the type of device, eg, a mobile relay or other low power device. The system information may also indicate that the BS allows it to be designated as a synchronization source by the SSM, that the BS indicates the synchronization sources of the same MNO network or PLMN required/preferred, and/or availability of an absolute timing source at the BS. and/or type of absolute timing source, such as GPS or PTP (IEEE 1588).

Neighbor information. Neighbor information may include a neighbor BS ID (eg PCI, ECGI or some other identifier) detected by the BS transmitting the SMR (eg from the neighbor's OSS or MIB/SIB), an indicator of a hierarchy of discovered neighbors and/or OSS signals containing an indication of the availability of an absolute timing source (eg GPS or PTP) in the neighbors (eg detected from the neighboring OSS or MIB/SIB) may include a list of neighbors in which they were found. An indicator of signal power or quality in terms of, for example, RSRP, RSRQ, or RSSI measurements of neighbors may also be included and expressed, for example, in dB units, watts or any derived units, averaged or It may be transmitted as a quantized version, or some other representation of these measurements.

Unavailability indicator. The unavailability indicator is a notification that the BS will cease operating as a synchronization source. The node unavailability indication may also include a list of elements that refer to neighboring BSs and indicate whether known neighboring synchronization sources cannot be detected by the BS transmitting the SMR, or are received with low power.

Synchronization management instructions

SMI messages may be transmitted via a backhaul from SSM to BS, as shown in FIG. 17 . SMIs may be used to indicate configuration updates or other information to the BS. SMIs may include any one or more of the following informational elements.

Requests for system and neighbor information. A request for system and neighbor information may prompt the BS receiving the SMI to send, in a subsequent SMR, its system information or neighbor information updates, or any of the information in the section above describing SMR messages. .

Neighbor discovery information about the receiving BS's neighbor (geographically local) synchronization sources. That information includes BS IDs (eg PCI, ECGI, etc.), some other index or identifier indicating the OSS training sequence transmitted by each neighbor, each neighbor's network (eg PLMN) ID, synchronization of neighbors an indicator of the hierarchy, and/or an indication of availability of absolute timing sources in neighbors (eg, GPS or PTP). The duty cycle of OSS or time/frequency resource mapping may also be included, which may be encoded in various formats, such as start and end indexes of time/frequency resources or a simple index to a lookup table of time/frequency resource indices. . Given an absolute timing reference, e.g., some millisecond offset within a window of one second, to indicate that a frame begins at that exact millisecond relative to some fixed timestamp, some standardized format, e.g., Coordinated Universal Time The ideal/absolute frame timing of each concatenated set may also be included, which may be expressed in Universal Time (UTC) time, or shortened to some shorter format that may be used to establish frame timing.

Assign a master synchronization source for the BS that receives the SMI. This information may include a BS ID or some sequence ID used to identify the OSS training sequence transmitted by the synchronization source. Secondary and tertiary synchronization source assignments may also be included, which may be used by the BS if the primary synchronization source becomes unavailable. The assignment also includes information about the setup of the synchronization source, such as random access channel resources, RACH preamble, or other physical channel information that may be used by the receiving BS communicating with the synchronization source to obtain, for example, timing advance. can do.

Setting the sync source for the recipient BS when the SSM assigns it to be the sync source. This information may include the PCI or OSS training sequence index to use, time/frequency resource mapping and/or duty cycle for OSS transmission, which may be encoded as described above. Power for transmitting OSS may also be included and expressed in dB units, watts or any derived units and as quantized formats. The SMI may also include an indication of a RACH resource and/or a preamble and/or other physical channel resources for reserving communications from one or more other BSs, which may also be indicated as described above.

26A illustrates a flowchart for transmitting SMRs in accordance with various embodiments of the present disclosure. The operations of flowchart 2600a may be implemented in a BS, such as BS 200 of FIG. 2 .

Flowchart 2600a begins at operation 2602 by detecting a trigger. The trigger may be a periodic trigger or an aperiodic trigger. In operation 2604, an SMR is sent to the SSM.

26B illustrates a flowchart for transmitting SMIs in accordance with various embodiments of the present disclosure. The operations of flowchart 2600b may be implemented in an SSM, such as SSM 406 of FIG. 4 .

Flowchart 2600b begins at operation 2606 by detecting a trigger. A trigger may be periodic or aperiodic. At operation 2608 , SMIs are sent to the BSs.

27A illustrates a signal flow diagram for transmitting SMRs in accordance with various embodiments of the present disclosure. BS A 2702 and SSM 2704 are in a shared spectrum network, such as network 400 of FIG. 4 . BS A 2702 sends an SMR to SSM 2404 at s2706. The SMR may be transmitted in response to detecting the triggering event as described in previous embodiments.

27B illustrates a signal flow diagram for transmitting SMIs in accordance with various embodiments of the present disclosure. BS A 2702 and SSM 2704 are in a shared spectrum network, such as network 400 of FIG. 4 . SSM2704) sends an SMI to BS A 2402 at s2708. The SMI may be transmitted in response to detecting a triggering event as described in previous embodiments.

Distributed discovery and association of new BS synchronization sources

In the disclosed distributed BS synchronization source discovery and association procedure shown in FIG. 28, BSs newly installed, or activated after some period of inactivity, discover neighboring synchronization sources and associate with a synchronization master without the support of a centralized entity such as SSM. . 28 shows a non-limiting example of distributed communication and coordination between BSs sharing spectrum to mutually determine master/slave synchronization source relationships. Any of the operations from the procedure of FIG. 28 may be omitted or performed in a different order. Also, the general procedure described herein may be applied to fewer or greater than three BS nodes described in this disclosure.

28 illustrates a signal flow diagram for adding a BS in a decentralized shared spectrum network according to various embodiments of the present disclosure. In this example, BS A 2802 is joining BS B 2804 and BS C 2806 in an established shared spectrum network, such as shared spectrum network 600a of FIG. 6A .

In S2808, BS A 2802 performs a neighbor discovery procedure by detecting OSS signals transmitted by neighbor synchronization sources. Additional system information such as BS ID, network ID and hierarchy indicator may be received from the neighbors' OSS or other MIB/SIB signals, as previously discussed.

At s2810 , BS B 2804 may transmit OSS to BS A 2802 , and may also transmit additional system information including a layer group indicator, in either OSS or MIB/SIB. At s2812 , BS C 2806 may transmit the OSS to BS A 2802 , and may also transmit additional system information including a layer group indicator, in either OSS or MIB/SIB.

In one embodiment, upon detecting one or more synchronization signals, BS A 2802 selects, as its initial synchronization source, one of the detected neighbors, eg, B and/or C. In this example of Figure 28, BS A 2802 selects BS B 2804 as its initial synchronization source.

In another embodiment, BS A 2802 may assume the role of a synchronization source and may configure itself to use some default synchronization parameters for transmission of the OSS. This may occur, for example, if no other synchronization sources are detected by BS A 2802 .

28 , the selection of BS B 2804 as a synchronization source for BS A 2802 may be lower than the hierarchy m of other neighbors, e.g., BS C 2806, indicated by BS B 2804. may be based on group n, or the determination may be based on other factors such as PLMN ID or received power.

BS A 2802 may then transmit a node advertisement, which is an over-the-air (OTA) signal to convey information about itself to its neighbors. In particular, BS A 2802 may send a node advertisement to BS B 2804 at s2816 and another node advertisement to BS C 2806 at s2818. Node advertisements may be sent in the coordination phase shown in FIG. 8 and information such as a list and hierarchy indicators of the selected master's BS ID and/or detected neighboring BS IDs, among other informational elements listed in the next section. may include Node advertisements can be broadcast to all neighbors or unicast to a specific neighbor.

Upon receiving the node advertisement, the neighbors of BS A 2808 may determine, based on some predetermined policy, that their settings should be updated due to the addition of BS A 2802 . For example, BS A 2802 may create interference for multiple BS nodes causing multiple connection sets to join, as previously described, where the master/slave hierarchy is recomputed. you may need In this example of s2820, BS B 2804 determines that BS C 2806 will be promoted to lower hierarchy x, and at s2822 BS C 2806 also determines that it will be promoted to lower hierarchy x. . In some embodiments, BS B 2804 has been demoted so that the hierarchy of BS C 2806 may now be lower than that of BS B 2804 . Stated differently, the master/slave relationship between BS B 2804 and BS C 2806 may change as a result of BS A 2802 joining the network, which may be changed between BS B 2804 and BS C 2806. is reflected by each stratum of BS B 2804 can thus be a slave of BS C 2806 .

At s2824 , BS B 2804 sends its node advertisement to BS A 2802 and at s2826 BS B 2804 sends its node advertisement to BS C 2806 . At s2828 , BS C 2806 sends its node advertisement to BS B 2804 and at s2830 BS C 2806 sends its node advertisement to BS A 2802 . The node advertisements transmitted at s2824, s2826, s2828, and s2830 may also include updated hierarchical group information. They can also send updated hierarchical settings as part of OSS or MIB/SIB.

At s2832 , BS A may select a new master, eg, BS C 2806 , based on OSS/MIB/SIB and/or received node advertisements from its neighbors with updated hierarchy settings.

Several iterations of updating the synchronization configuration and sending node advertisements will be repeated until the master/slave synchronization hierarchy is stable and all BSs in the connection set determine that no further updates are needed for a given state of the network topology and BS settings. can

Distributed Synchronization Source Reconfiguration

Other types of topology changes, for example resulting from the synchronization source becoming unavailable or changing interference relationships, are also similar to the centralized synchronization source reconfiguration procedure described previously but without support from the centralized SSM. It can trigger a distributed re-establishment of master/slave synchronization relationships that occur.

29 illustrates a signal flow diagram for removing a BS in a decentralized shared spectrum network according to various embodiments of the present disclosure. In this example, BS A 2902 , BS B 2904 , and BS C 2906 are in a distributed, shared spectrum network, such as network 600a of FIG. 6 . In addition, BS A 2902 is the synchronization source for BS B 2904 and BS C 2906 and is informing its neighboring BSs that it will become unavailable.

At s2908 , BS A 2902 sends a node unavailability indication message regarding its pending deactivation to BS B 2904 . In s2910, BS A 2902 sends a node unavailability indication message regarding its pending deactivation to BS C 2906. The node unavailability message may be part of the node advertisement sent during the reconciliation phase. Alternatively, the node unavailable message may be a unicast inter-BS control message sent directly to one or more BSs using their respective uplink channel resources. In other embodiments, instead of BS A 2902 notifying its neighbors that it will be unavailable in a node unavailability indication message, its neighbors BS A 2902, their respective synchronization source, is the OSS can no longer be transmitted and therefore not available as a synchronization source.

At s2912 , BS B 2904 updates its settings in response to receiving the node unavailability indication message at s2908 . Similarly, at s2914, BS C 2906 updates its settings in response to receiving the node unavailability indication message at s2910. At s2916 , BS B 2904 sends an updated node advertisement to BS A 2902 and at s2918 , BS B 2904 sends an updated node advertisement to BS C 2906 . At s2920 , BS C 2906 sends an updated node advertisement to BS A 2902 and at s2922 , BS C 2906 sends an updated node advertisement to BS B 2904 .

Several iterations of updating the synchronization configuration and sending node advertisements will be repeated until the master/slave synchronization hierarchy is stable and all BSs in the connection set determine that no further updates are needed for a given state of the network topology and BS settings. can

Synchronization information request and response between BSs and timing advance

Following the initial synchronization source discovery and association procedures, the centralized embodiment is shown in FIG. 18 and the distributed embodiment is shown in FIG. 28, or at any time subsequent to the initial association, the BSs may exchange information for synchronization purposes. It can communicate with other BSs. 16A and 16B show the exchange of information request and response between BSs between two BSs in a shared spectrum network. One non-limiting example where such communication may be useful is for the acquisition of timing advance from its synchronization master by a synchronization slave. Timing advance may be useful for performing finer timing alignment by the synchronization slave.

30 illustrates timing alignment between a synchronization source and a slave BS in accordance with various embodiments of the present disclosure. Timing alignment may be achieved between base stations of a shared spectrum network, such as network 400 of FIG. 4 , or network 600a of FIG. 6A .

As illustrated in FIG. 30 , the OSS 3002 transmitted by the synchronization source BS A may not be sufficient to align the transmission times of CSS frames with high accuracy. Propagation of OSS 3002 over some distance between BS A and BS B receiving OSS 3002 of BS A will result in OSS 3002 being received at a delay 3004 after the time it was transmitted. Thus, if BS B is based on its frame timing of the time it receives OSS 3002, the frame timing will be delayed compared to other synchronized BSs in the same connection set. To compensate for this propagation delay, BS B may perform the inter-BS information request procedure described in FIG. 31 . This procedure may involve sending a random access signal 3006 to BS A. This random access signal 3006 may be similar to the RACH preamble of LTE. However, instead of facilitating random access by the UE, it is used for fine time synchronization between BSs, such as BS A and BS B. The random access signal 3006 will be received at BS A with an offset of approximately 3008 at appropriate frame timing, assuming that propagation from BS A to BS B and from BS B to BS A is approximately uniform. From this, BS A can compute the timing advance (TA) to be applied by BS B. The random access signal 3006 may be followed by a random access response (RAR) signal 3010 from the synchronization source BS A, which may include TA information. TA may be expressed similarly to LTE TA as the number of samples to be offset from the coarse timing derived from OSS, or may be expressed as a time value.

Inter-BS information request/response messages may also be used to transmit additional synchronization control information between BSs. For example, an explicit instruction for the BS to change its synchronization master to a different BS. This inter-BS information can be applied to both the previously disclosed centralized and distributed procedures.

31 illustrates a signal flow diagram for timing alignment between a synchronization source and a slave BS in accordance with various embodiments of the present disclosure. BS B 3102 and BS A 3104 are in a distributed, shared spectrum network, such as network 400 of FIG. 4 or network 600a of FIG. 6 . In addition, BS A 3104 is the synchronization source for BS B 3102 .

In s3106, BS B 3102 transmits a random access signal to BS A 3104. An example of this random access signal is the random access signal 3006 of FIG. 30 . At s3108 , BS A 3104 sends a random access response (RAR) to BS B 3102 . The RAR may include a usable timing advance to establish BS B 3102 . An example of this RAR is the RAR 3010 of FIG. 30 .

32 illustrates a flowchart for timing alignment at a slave BS according to various embodiments of the present disclosure. The operations of flowchart 3200 may be implemented in a BS, such as BS 200 of FIG. 2 .

Flowchart 3200 begins at operation 3202 by receiving an OSS from a neighboring synchronization source BS. In operation 3204, random access resource information is obtained from system information transmitted from the synchronization source BS. At operation 3206 , a random access preamble is transmitted to the synchronization source BS.

In operation 3208, a determination is made as to whether a random access response (RAR) with propagation delay information is received from a neighboring synchronization source BS. If the RAR with propagation delay information is not received from the synchronization source BS, the flowchart 3200 proceeds from operation 3208 to operation 3210 where the power for preamble transmission is increased. Flowchart 3200 then proceeds from operation 3210 back to operation 3206 .

Returning to operation 3208, if a determination is made that a RAR with propagation delay information is received from the synchronization source BS, the flowchart 3200 proceeds to operation 3212 where the frame timing from the received OSS timing is advanced by an amount of a propagation delay value. . At operation 3214, an acknowledgment is sent to the synchronization source BS.

33 illustrates a flowchart for timing alignment at a synchronization source BS in accordance with various embodiments of the present disclosure. Flowchart 3300 may be implemented in a BS, such as BS 200 of FIG. 2 .

Flowchart 3300 begins at operation 3302 by receiving a preamble signal from a sync slave BS. In operation 3304, a propagation delay is estimated from the synchronous slave BS. In operation 3306, propagation delay information is sent to the synchronous slave BS. The propagation delay information may be used by the synchronous slave BS to compute the timing delay information.

In operation 3308, a determination is made as to whether an acknowledgment is received from the sync slave BS. If an acknowledgment is not received from the sync slave BS, the flow chart 3300 proceeds from operation 3308 to operation 3302 . However, if an acknowledgment is received at the synchronous slave BS, the flowchart ends.

UE Timing Adjustment Instruction During Serving Cell Timing Update

As previously discussed in this disclosure, BSs in a shared spectrum network may need to change their approximate frame timing according to, for example, centralized or distributed synchronization source update procedures. When this happens, UEs may lose synchronization to their serving BS and may have to perform the initial attach procedure again to re-establish communication with the serving BS, which may potentially lead to service disruption.

34 illustrates a signal flow diagram for a UE timing adjustment update procedure according to various embodiments of the present disclosure. BS A 3402 is a BS in a shared spectrum network, such as network 400 of FIG. 4 or network 600a of FIG. 6A . In addition, BS A 3402 is the serving BS for UE 3404 .

In s3406, BS A 3402 updates its frame timing. To notify the UE 3404 of the pending change to the timing of BS A 3402 , BS A 3402 sends a UE Timing Adjustment message at s3408 . The timing adjustment message may contain a timing offset to be applied expressed in units of time (which may be encoded in some standardized format such as UTC), a number of samples, or some number of symbols (e.g., OFDM symbols) or number of time slots. . UE timing adjustments may also include an indication of when the timing adjustments should be applied to, for example, any future frame, subframe, slot, symbol or sample index, as absolute time/index or relative offset time/index. can be expressed The UE timing adjustment may be included in a Radio Resource Control (RRC) message or similar control message as in LTE. In s3410, the UE applies the timing adjustment accordingly.

Dedicated sync source wireless node

As an alternative to the previously disclosed inter-BS OTA synchronization methods for shared spectrum networks, a system of dedicated synchronization source nodes is provided in FIG. 35 .

In particular, FIG. 35 illustrates an architecture for a dedicated synchronization source in accordance with various embodiments of the present disclosure. System 3500 may be included in a shared spectrum network, such as network 400 of FIG. 4 or network 600a of FIG. 6A .

System 3500 is a dedicated synchronization source that is wireless devices that transmit OSS for the purpose of providing synchronization to one or more base stations, such as BSs 3504a, 3504b, 3504c, 3504d, and 3504e, that may belong to multiple MNO networks. DSSs) 3502a and 3502b. DSS nodes 3502 may broadcast OSS over a large geographic area. Multiple DSSs may deploy and share a common absolute reference timing provided by, for example, a GPS or backhaul PTP system. The DSS may transmit OSS on a dedicated physical channel reserved for this purpose or may be transmitted on physical channel resources used for communications by BSs.

The network of DSS nodes 3502 may also be augmented by OTA synchronization between BSs as shown in FIG. 35 . For example, a DSS may be considered a root (tier 0) synchronization source, while BSs synchronized to a DSS may operate as secondary (tier 1) synchronization sources. In FIG. 35 , BSs 3504a , 35304b , 3504d , and 3504e may be treated as first hierarchical sources. In this example of FIG. 35 , BS 3504c is the second tier source. Inter-BS synchronization may still be necessary in some cases where the OSS transmitted by the DSS may or may not be received with sufficiently high power by the BS. The DSS may also have an uplink channel for feedback from the BSs to request timing advance information, for example, which may be a dedicated physical channel or a physical channel shared by the BSs.

36 illustrates a flow diagram of a process for synchronization of shared spectrum networks in accordance with various embodiments of the present disclosure. The operations of flowchart 3600 may be implemented with a shared spectrum manager, such as SSM 406 of FIG. 4 .

At operation 3602 , synchronization measurement reports (SMRs) are received from a plurality of BSs.

At operation 3604 , the at least one synchronization source BS and the at least one slave BS are identified from the plurality of BSs based on the SMRs. In one embodiment, the transmission timing of the at least one slave BS is based on the transmission timing of the at least one synchronization source BS.

In one embodiment, identifying the at least one synchronization source BS comprises identifying interference relationships between the plurality of BSs, identifying one or more sets of BS connectivity based on the identified interference relationships, the one or more BS connectivity identifying at least one synchronization source BS for each BS-connected set of the sets, and identifying a slave BS in the at least one BS-connected set of the one or more BS-connected sets. In this embodiment, BSs in a BS-connected set do not interfere with BSs in other BS-connected sets.

In operation 3606, the at least one synchronization source BS is assigned to a hierarchy in the synchronization hierarchy. The synchronization source BS assigned to the n=0 hierarchy provides the reference frame timing for a plurality of BSs. A synchronization source BS assigned to n>0 hierarchy derives frame timing from another synchronization source BS assigned to n-1 hierarchy. In any one event, the at least one synchronization source BS sends an over-the-air (OTA) synchronization signal to one of the at least one slave BS or at least one other synchronization source BS assigned to the n+1 hierarchy. send OSS.

In one embodiment, the synchronization source BS assigned to the n=0 hierarchy transmits the first OSS in a first frame and the synchronization source BS assigned to the n>0 hierarchy transmits the first OSS in a second frame different from the first frame. 2 Send OSS. For example, each synchronization source BS of the at least one synchronization source BS is a frame in which L is the supported level of synchronization source BSs in the synchronization hierarchy, n is an integer, and k is a frame offset based on the assigned hierarchy. Transmit each OSS at number (L*n + k).

In another embodiment, the synchronization source BS assigned to the n=0 hierarchy transmits the first OSS in a first time interval of a frame and the synchronization source BS assigned to the n>0 hierarchy transmits the first OSS in the second time interval of that frame transmit the second OSS to The first OSS and the second OSS include respective timing offsets based on their respective hierarchical groups, and frame timing for the receiver of the first OSS or the second OSS is derived based on the respective timing offsets. When the support level of the synchronization source BSs changes, a number of time intervals are also changed based on the changes in the support level of the synchronization source BSs.

In operation 3608, synchronization signals are established and in operation 3610 synchronization management indications (SMIs) are transmitted to the plurality of BSs. SMIs include (i) configured synchronization signals, (ii) an assigned hierarchy, and (iii) synchronization source/slave assignments.

In some embodiments, receiving the SMRs includes receiving an SMR indicating the unavailability of the BS at the plurality of BSs in operation 3602 . In these embodiments, operation 3602 may also include determining interference relationships between remaining BSs in the plurality of BSs based on the unavailability of the BS. The updated SMIs may then be transmitted to one or more BSs in the remaining BSs based on the determined interference relationships. Updated SMIs include updated synchronization source/slave assignments.

In some embodiments, when the plurality of BSs includes an unassigned BS, such as when a BS is newly added to the system or thereafter when the BS is turned on again after a PNO event, the flow diagram 3600 is the following FIG. 37 . It may include additional operations described in .

37 illustrates a flow diagram of a process for managing shared spectrum networks with an unassigned BS in accordance with various embodiments of the present disclosure. The operations of flowchart 3700 may be implemented with a shared spectrum manager, such as SSM 406 of FIG. 4 .

In operation 3702, a request for SMI is received from an unassigned BS. In operation 3704, a first SMI is transmitted to the unassigned BS. The first SMI includes neighbor discovery support. At operation 3706 , an SMR is received from an unassigned BS. The SMR includes a list of discovered neighbors and interference information. Thereafter, a second SMI is transmitted to the unassigned BS in operation 3708 . The second SMI includes at least one of a hierarchy assignment or a synchronization source/slave assignment. In operation 3710, the updated SMIs are transmitted to at least some of the plurality of BSs based on the hierarchy assignment or the synchronization source/slave assignment to the unassigned BS.

38 illustrates an electronic device in accordance with embodiments of the present disclosure.

Referring to FIG. 38 , the electronic device 3800 may include a processor 3810 , a transceiver 3820 , and a memory 3830 . However, not all of the illustrated components are essential. Electronic device 3800 may be implemented with more or fewer components than those illustrated in FIG. 38 . Additionally, the processor 3810 , the transceiver 3820 , and the memory 3830 may be implemented as a single chip according to another embodiment.

The electronic device 3800 may correspond to the electronic device described above. For example, the electronic device 3800 may correspond to the electronic device 300 illustrated in FIG. 3 .

The aforementioned components will now be described in detail.

The processor 3810 may include one or more processors or other processing devices that control the proposed function, process, and/or method. The operation of the electronic device 3800 may be implemented by the processor 3810 .

The transceiver 3820 may include an RF transmitter for up-converting and amplifying a transmitted signal, and an RF receiver for down-converting a frequency of a received signal. However, according to another embodiment, the transceiver 3820 may be implemented by more or fewer components than those shown as components.

The transceiver 3820 may be connected to the processor 3810 and transmit and/or receive signals. The signal may include control information and data. Also, the transceiver 3820 may receive a signal through a wireless channel and output the signal to the processor 3810 . The transceiver 3820 may transmit a signal output from the processor 3810 through a wireless channel.

The memory 3830 may store control information or data included in a signal obtained by the electronic device 3800 . Memory 3830 may be coupled to processor 3810 and store at least one command or protocol or parameter for a proposed function, process, and/or method. Memory 3830 may include read-only memory (ROM) and/or random access memory (RAM) and/or a hard disk and/or CD-ROM and/or DVD and/or other storage devices.

39 illustrates a base station according to embodiments of the present disclosure.

Referring to FIG. 39 , the base station 3900 may include a processor 3910 , a transceiver 3920 , and a memory 3930 . However, not all of the illustrated components are essential. The base station 3900 may be implemented by more or fewer components than the components illustrated in FIG. 39 . Additionally, the processor 3910 , the transceiver 3920 , and the memory 3930 may be implemented as a single chip according to another embodiment.

The base station 3900 may correspond to the gNB described above. For example, the base station 3900 may correspond to the BS 200 illustrated in FIG. 2 .

The aforementioned components will now be described in detail.

The processor 3910 may include one or more processors or other processing devices that control the proposed function, process, and/or method. The operation of the base station 3900 may be implemented by the processor 3910 .

The transceiver 3920 may include an RF transmitter for up-converting and amplifying a transmitted signal, and an RF receiver for down-converting a frequency of a received signal. However, according to another embodiment, the transceiver 3920 may be implemented by more or fewer components than those illustrated as components.

The transceiver 3920 may be connected to the processor 3910 and transmit and/or receive signals. The signal may include control information and data. Also, the transceiver 3920 may receive a signal through a wireless channel and output the signal to the processor 3910 . The transceiver 3920 may transmit a signal output from the processor 3910 through a wireless channel.

The memory 3930 may store control information or data included in a signal obtained by the base station 3900 . The memory 3930 may be coupled to the processor 3910 and store at least one command or protocol or parameter for the proposed function, process, and/or method. Memory 3930 may include read-only memory (ROM) and/or random access memory (RAM) and/or a hard disk and/or CD-ROM and/or DVD and/or other storage devices.

Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to those skilled in the art. This disclosure is intended to cover such changes and modifications as fall within the scope of the appended claims.

Claims (15)

An electronic device for managing a shared spectrum between a plurality of base stations (BSs), the electronic device comprising:
a memory containing instructions for managing the shared spectrum; and
receiving synchronization measurement reports (SMRs) from the plurality of BSs;
identify at least one synchronization source BS and at least one slave BS from the plurality of BSs based on the SMRs;
allocating the at least one synchronization source BS to a hierarchy in a synchronization hierarchy;
configure synchronization signals, and
at least one processor for transmitting synchronization management indications (SMIs) comprising (i) configured synchronization signals, (ii) an assigned hierarchy, and (iii) synchronization source/slave assignments to the plurality of BSs; including,
the transmission timing of the at least one slave BS is based on the transmission timing of the at least one synchronization source BS;
allocating the at least one synchronization source BS, the synchronization source BS assigned to the n=0 hierarchy provides reference frame timing for the plurality of BSs; and
An electronic device comprising: a synchronization source BS assigned to n>0 hierarchy deriving frame timing from another synchronization source BS assigned to n-1 hierarchy. According to claim 1,
the at least one processor,
The at least one synchronization source BS provides over-the-air (OTA) synchronization signals (OSS) to at least one other synchronization source BS assigned to an n+1 hierarchical group or to one slave BS of the at least one slave BS. send, and
When the at least one synchronization source BS includes the synchronization source BS allocated to the n=0 hierarchy and the synchronization source BS allocated to the n>0 hierarchy, the synchronization source BS allocated to the n=0 hierarchy wherein the synchronization source BS transmits a first OSS in a first frame and the synchronization source BS assigned to the n>0 hierarchy transmits a second OSS in a second frame different from the first frame device. According to claim 1,
the at least one processor,
The at least one synchronization source BS provides over-the-air (OTA) synchronization signals (OSS) to at least one other synchronization source BS assigned to an n+1 hierarchical group or to one slave BS of the at least one slave BS. send, and
When the at least one synchronization source BS includes the synchronization source BS allocated to the n=0 hierarchy and the synchronization source BS allocated to the n>0 hierarchy, the synchronization source BS allocated to the n=0 hierarchy the synchronization source BS transmits a first OSS in a first time interval in a frame and the synchronization source BS assigned to the n>0 hierarchy transmits a second OSS in a second time interval in the frame An electronic device comprising. According to claim 1,
the at least one processor,
identify interference relationships between the plurality of BSs;
based on the identified interference relationships, the BSs in a BS-connected set identify one or more BS-connected sets that do not interfere with BSs in another BS-connected set;
identify at least one synchronization source BS for each BS-connected set of the one or more BS-connected sets, and
The electronic device further comprising: identifying a slave BS in at least one BS-connected set of the one or more BS-connected sets. According to claim 1,
The plurality of BSs include unassigned BSs,
the at least one processor,
Receiving a request for a first SMI from the unassigned BS,
transmit the first SMI including neighbor discovery support to the unassigned BS;
Receive an SMR including a list of neighbors and interference information found from the non-assigned BS,
transmit to the unassigned BS a second SMI including a hierarchy assignment or a synchronization source/slave assignment for the unassigned BS; and
The electronic device further comprising transmitting updated SMIs to at least some of the plurality of BSs based on the hierarchy assignment or the synchronization source/slave assignment to the unassigned BS. According to claim 1,
When receiving SMRs including information indicating the unavailability of the BS in the plurality of BSs,
the at least one processor,
determine interference relationships between the remaining BSs in the plurality of BSs based on the unavailability of the BS, and
and transmitting updated SMIs comprising updated synchronization source/slave assignments to one or more BSs in the remaining BSs based on the determined interference relationships. A method for managing a shared spectrum between a plurality of base stations (BSs) performed by an electronic device, the method comprising:
receiving synchronization measurement reports (SMRs) from the plurality of BSs;
identifying at least one synchronization source BS and at least one slave BS from the plurality of BSs based on the SMRs;
allocating the at least one synchronization source BS to a hierarchy in a synchronization hierarchy;
constructing synchronization signals; and
sending to the plurality of BSs synchronization management indications (SMIs) comprising (i) configured synchronization signals, (ii) an assigned hierarchy, and (iii) synchronization source/slave assignments; and,
the transmission timing of the at least one slave BS is based on the transmission timing of the at least one synchronization source BS;
Allocating the at least one synchronization source BS comprises:
providing, by a synchronization source BS assigned to an n=0 hierarchy, reference frame timing for the plurality of BSs; and
Managing shared spectrum among a plurality of BSs performed by an electronic device comprising; a synchronization source BS assigned to n>0 hierarchy deriving frame timing from another synchronization source BS assigned to n-1 hierarchy How to. 8. The method of claim 7,
A method for managing a shared spectrum between a plurality of BSs performed by the electronic device,
The at least one synchronization source BS provides over-the-air (OTA) synchronization signals (OSS) to at least one other synchronization source BS assigned to an n+1 hierarchical group or to one slave BS of the at least one slave BS. sending and
Based on the at least one synchronization source BS comprising the synchronization source BS allocated to the n=0 hierarchy and the synchronization source BS allocated to the n>0 hierarchy, the n=0 hierarchy is assigned The synchronization source BS transmits a first OSS in a first frame and the synchronization source BS assigned to the n>0 hierarchical group transmits a second OSS in a second frame different from the first frame; A method for managing a shared spectrum between a plurality of BSs performed by an electronic device comprising: 8. The method of claim 7,
A method for managing a shared spectrum between a plurality of BSs performed by the electronic device,
The at least one synchronization source BS provides over-the-air (OTA) synchronization signals (OSS) to at least one other synchronization source BS assigned to an n+1 hierarchical group or to one slave BS of the at least one slave BS. sending and
Based on the at least one synchronization source BS comprising the synchronization source BS allocated to the n=0 hierarchy and the synchronization source BS allocated to the n>0 hierarchy, the n=0 hierarchy is assigned wherein the synchronization source BS transmits a first OSS in a first time interval in one frame and the synchronization source BS assigned to the n>0 hierarchy transmits a second OSS in a second time interval in the frame; A method for managing a shared spectrum between a plurality of BSs performed by an electronic device further comprising a. 8. The method of claim 7,
The step of identifying the at least one synchronization source BS and the at least one slave BS comprises:
identifying interference relationships between the plurality of BSs;
identifying one or more BS-connected sets based on the identified interference relationships, wherein BSs in a BS-connected set do not interfere with BSs in another BS-connected set;
identifying at least one synchronization source BS for each BS-connected set of the one or more BS-connected sets; and
identifying a slave BS in at least one of the one or more BS-connected sets. 8. The method of claim 7,
The plurality of BSs include unassigned BSs,
A method for managing a shared spectrum between a plurality of BSs performed by the electronic device,
receiving a request for a first SMI from the unassigned BS;
transmitting the first SMI including neighbor discovery support to the unassigned BS;
receiving an SMR including a list of discovered neighbors and interference information from the unassigned BS;
transmitting to the unassigned BS a second SMI including a hierarchy assignment or a synchronization source/slave assignment for the unassigned BS; and
transmitting updated SMIs to at least some of the plurality of BSs based on the hierarchy assignment to the unassigned BS or the synchronization source/slave assignment; How to manage the shared spectrum between BSs. 8. The method of claim 7,
Receiving the SMRs includes receiving an SMR indicating the unavailability of a BS in the plurality of BSs,
A method for managing a shared spectrum between a plurality of BSs performed by the electronic device,
determining interference relationships between remaining BSs in the plurality of BSs based on the unavailability of the BS; and
transmitting updated SMIs comprising updated synchronization source/slave assignments to one or more BSs in the remaining BSs based on the determined interference relationships; A method for managing shared spectrum between BSs. In the base station (BS),
a processor configured to generate a Synchronization Measurement Report (SMR); and
transmit the SMR;
Receive synchronization management signals (SMI) comprising at least one of (i) configured synchronization signals, (ii) an assigned hierarchy of a synchronization hierarchy (n), or (iii) synchronization source/slave assignments;
In response to the transceiver receiving the assigned hierarchical group (n), in the synchronization hierarchy, at least one of the other synchronization source BS or the at least one slave BS allocated to the n+1 hierarchical group is -air) transmit a set of synchronization signals (OSS),
when the BS is assigned to n=0 hierarchy, the BS transmits the OSS set without reference to frame timing from another synchronization source BS;
and a transceiver for transmitting the OSS set based on frame timing derived from another synchronization source BS assigned to the n-1 hierarchical group, when the BS is assigned to n>0 hierarchical group. 14. The method of claim 13,
The BS is,
L is the supported level of synchronization source BSs in the synchronization hierarchy, n is an integer, and k is the frame offset based on the assigned hierarchy;
Transmit the OSS set in frame number (L*n + k) or
When the BS is assigned to the n=0 hierarchical group, a first time interval in one frame, or
and transmit the OSS set in one of a second time interval in the frame if the BS is the n>0 layer group. A method of network synchronization for a shared spectrum performed by a base station (BS), the method comprising:
Receiving synchronization management signals (SMI) comprising at least one of (i) configured synchronization signals, (ii) an assigned hierarchy of a synchronization hierarchy (n), or (iii) synchronization source/slave assignments. ;
In response to receiving the assigned hierarchy n, over-the-air (OTA) to at least one of at least one slave BS or another synchronization source BS assigned to an n+1 hierarchy in the synchronization hierarchy. transmitting a set of synchronization signals (OSS);
when the BS is assigned to an n=0 hierarchy, the BS transmits the OSS set from another synchronization source BS without reference to frame timing; and
When the BS is assigned to n>0 hierarchies, the BS transmits the OSS set based on frame timing derived from other synchronization source BSs assigned to n-1 hierarchies; A method of network synchronization for shared spectrum performed by

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